Ground clamp for electrical circuits



April 10, 1951 A. B. DOWNS, JR 2,547,932

GROUND CLAMP FOR, ELECTRICAL CIRCUITS Filed Nov. 8, 1946 IN VE N TOR.

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ATTORNEY Patented Apr. 10, 19 51 GROUND CLAMP FOB, ELECTRICAL CIRCUITS Alfred B- Dcwns, Jr-, Columbu Application November 8, 1946, Serial No. 708,539 8 Claims. (01. 173-273) My invention relates broadly to electrical connectors and more particularly to a simplified construction of electrical grounding or terminal clamp for establishing a permanent electrical connection with a ground rod, pipe, storage battery electrode, or other type of electrical terminal. One of the objects of my invention is to provide a simplified construction of an electrical grounding or terminal clamp which may be quickly installed for establishing a reliable electrical connection with a ground rod, pipe or electrode.

Another object of my invention is to provide a construction of electrical grounding or terminal clamp which may be manufactured inexpensively on a mass production scale utilizing a minimum number of parts and insuring a quick and reliable electrical connection with an electrical conductor.

Another object of my invention is to provide an improved construction of adjustable clamp which may be readily and conveniently fitted to .a ground rod, pipe, or electrode of various size, for establishing reliable electrical connection with an electrical conductor.

Still another object of my invention is to provide a construction of adjustable clamp for effecting connection between an electrical conductor and a ground rod, pipe, or electrode in which the [clamping of the electrical conductor is accomplished simultaneously with the adjustment of the clamp in position on the ground rod, pipe, or electrode.

Other and further objects of my invention re- :side in an arrangement of an anvil-like pressure actuated member for clamping an electrical con- .ductor in position with relation to a ground rod, pipe, or electrode, as set vforth more fully in the specification hereafter following by reference to the accompanying drawings, in which: I

Figure l is a top plan View of one form of electrical grounding or terminal clamp embodying my invention and applied to a pipe, with parts of the clamp broken away and illustrated in section; Fig. 2 is a side elevational View of the clamp illustrated in Fig. 1 with a portion thereof broken away and shown in section; Fig. 3 is a transverse sectional view taken on line 3--3 of Fig. 1; Fig. 4 is a top plan view similar to the view illustrated in Fig. l, but showing the clamp applied to a pipe of larger cross-sectional diameter for illustrating the manner of applying the clamp of my invention to pipes of various diameters; Fig. 5 is a fragmentary view of the pres sure actuated anvil member slidable within one portion of the clamp for establishing connection with an electrical conductor; Fig. 6 is a transverse sectional view taken through the portion of the clamp illustrated in Fig. 5 and showing the pressure actuatedanvil member in a position for clamping an electrical conductor with respect to one of the clamping members; Fig. 7 is a fragmentary sectional view taken on line of Fig. 5; Fig. 8 is an elevational view of the pressure actuated anvil member which establishes clamping relation with the electrical conductor inserted through the apertured portion of the clamping member illustrated in Figs. 5 and 6; Fig. 9 is a top plan view of a modified form of electrical grounding or terminal clamp embodying my invention with certain of the arts broken away and illustrated in section; Fig. 10 is a side elevational view of the clamp illustrated in Fig. 9. looking in the direction of r w A; a d. F 11 is an end elevational View of the mp i trated in Fig. .9 lockin in the direction of a r B thereof.

Referrin to thedraw ns i d a l. e e e characte I d signates. a p pe p esentat e of a round, rod or ele rode to which el ct ica ect n is to be made by e ect c nductor 2. T e elec rical r unding or t m lc p'cc ri es a pai .c tran ve ba m ers ep etented at ar d avi g i r f c 3 d 4 w i bstantia ly ccn crm to the @9 the surface of the ground rod, pipe, or electrode, represented at l, with which electrical connection i o be estab ed,- T c rms t a 4 ha @Xe tended lugs 3b and All which extend in substantially spaced parallel relation. Lug 4b is apert i d. nest is bifurcated or slotted asrepresented 36 ior'the passage of the headed bolt 5. Thehead- 5c of the headed bolt 5 extends over the bifurcated or slotted portion 30 of the lug 3? for securingthe arm '3 in position against the circular surface of thepipe' I. The headed bolt ,5 has'a's. ew threa ed end 519 which engages s rewthreads inlus 4b tfor'securing'arm 4 relative t the curved surfaceof pipe 1.

The opposite ends of arms 3 and 4 are interconnected bY means of an adjustable latch arm shown at 6 The latch arm is connected with arm 3 of the clam'pin a very special manner. Arm 3 is bifurcated or slotted adjacent its extremity .1 represented at 91. The bifurcation or slot 311 ex ends c ntrally of the end of a m 3 a d in ludes a pair of angularly inclined inte ral faces represented at 3e and 3f di ted rd each other. The ansu a ly nc ined faces 3;: and 3 meet an apex 3g forming a recess which is engageable by the tooth 6a of the latch arm 6. The latch arm 6 has a transversely extending elongated slot 61) adjacent the end thereof which is engageable over pin member 371. which extends transversely through arm 3. The latch arm 6 is thus provided with sufficient lost motion to permit the latch arm to be removed in a direction substantially normal to the axis of arm 3 for freeing the tooth 6a from the recess 3g and permitting the latch 6 to be swung to the dotted line position 6 as illustrated in Figure 1, or shifted to full line position with the tooth 6a engaged in recess 3g. The latch arm 6 is provided with a multiplicity of spaced latch teeth which I have represented at 60, 6d, Be and 6f. These latch teeth are provided in spaced positions for allowing adjustment of the clamp to fit various sizes of ground rods, pipes, or electrodes, represented by I in Figure l. The front faces of the latch teeth 60, 6d, Be and 63 are inclined at an acute angle in the direction of the confined end of the latch '6. The rear faces of the latch teeth 60, 6d, 6e and 6 all extend normal to the axis the latch B. I shape the latch teeth in this manner in order to facilitate the engagement thereof with the end of arm 4.

Arm 4 has the end thereof bifurcated or slotted at 40 with the interior of the bifurcated end recessed by the juncture of an inclined face 4d with a face 4e extending substantially normal to the slotted end 40 and meeting at an apex 4f, providing a pocket or notch in which any one of the latch teeth 60, 6d, Be or Bi may be selectively engaged. The arm 4 is provided with an aperture I which extends in a position substantially central of arm 4 and in a direction substantially normal to the plane thereof. The aperture I is connected through an opening 8 with the interior face 4a of arm 4 in the direction of the ground rod, pipe or electrode which is to be gripped. I provide a pressure actuated anvil member 9 slidable through the opening 8 in a direction transverse to the axis of arm 4. The pressure actuated anvil member 9 is provided with a contact engaging head 9a which is substantially frusto-conical in shape which is integrally connected with the slotted portion 9b of the pressure actuated anvil member 9. The slotted portion 9b provides a pair of arms 90 and 9d which are expanded outwardly and form anvil faces 9e and 9f movable interiorly of aperture 1 and engageable by the electrical conductor 2. The fact that the ends 90 and 9d are spread relatively to each other insures the retention of the pressure actuated anvil member 9 in the arm 4 while being free to slide through opening 9.

Thus when the connecting wire 2, which is generally bare and free of insulation, is inserted through aperture 1 in arm 4 the surface of wire 2 engages anvil faces 9e and 9 of the pressure actuated anvil member 9, thus displacing the pressure actuated anvil member 9 from the position shown in Fig. to the position shown in Fig. 6 and engaging the contacting end 9a thereof with the surface of the ground rod, pipe, or electrode I.

The clamp is applied to the ground rod, pipe or electrode I by adjusting bolt 5 to allow sufficient spreading of arms 3 and 4 and then the arms moved around the ground rod, pipe, or electrode I with latch arms 6 in the dotted line position, indicated at 6'. The connecting wire 2 is inserted through aperture I thereby projecting pressure actuated anvil member 9 through opening 8 and engaging contact 9a with the groundrod, pipe, or electrode I. Latch arm 6 is then moved to the full line position shown in Fig. 1, engaging tooth Ed in recess 4d, 4 4c, in arm 4. Bolt 5 is then turned to firmly anchor the clamp on the ground rod, pipe, or electrode I. The pressure thus applied forces pressure actuated anvil member 9 in more intimate contact with electrical conductor 2 establishing good electrical connection between anvil faces 9e and Si and electrical conductor 2. The same pressure applying force which clamps the arms 3 and 4 in position with respect to ground rod, pipe, or electrode I, firmly binds electrical conductor 2 in intimate contact with arm 4.

As illustrated in Fig. 4 the clamp of my invention is applicable to ground rods, pipes, or electrodes of various sizes, and may be adjusted to connect for such different sizes. In Fig. 4 I have shown the clamp of my invention applied to a pipe I of such diameter that latch tooth 6c is engaged with the recessed end of the arm 4 rather than the latch tooth 6d as illustrated in Fig. 1.

Figs. 9, 10 and 11 show a modified form of my invention in which a latch arm II) is pivotally mounted at 31' in the slotted end 39' of the arm 3. I have employed similar reference characters to designate arms 3 and 4 connected by bolt 5 in the form of my invention shown in Figs. 9-11 in order to readily compare the structures of Figs. 1-3 with the modified constructions of Figs. 9-11. It will be understood that the ends of arms 3 and 4 in the form of my invention shown in Figs. 9-11 are treated in a manner wholly different from the arrangement in the construction illustrated in Figs. 1-3. The end of arm 4 is bifurcated or slotted as represented at 471. for the passage of the swingable latch III. A transverse pin 42' extends across the slotted end 4h of arm 4. The latch arm I0 is provided with angularly inclined recesses shown at IIIa, IOb, I00, Id and Inc, which may be readily engaged over transverse pin 4i by swinging latch ID from the dotted line position III to the full line position II]. Thus adjustment of the clamp in the form of my invention illustrated in Figs. 22-11 is effected by selective interconnection of an externally arranged set of recesses with pin members 4i as distinguished from the inwardly directed latch teeth 60, 6d, 56 and (if on the latch in the form of my invention shown in Figs. 1-3.

The balance of the structure of the clamp in the form of my invention shown in Figs. 9-11 is similar to the structure heretofore explained in Figs. 1-8, that is to say, the pressure actuated anvil 9 is moved to clamping position with respect to electrical conductor 2 simultaneously with the adjustment of the clamp arms 3 and 4 on the ground rod, pipe, or electrode I.

The clamp arms and latch arm may be readily cast from material, or otherwise formed from material, of good electrical conductivity.

While I have described my invention in certain of its embodiments I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than those imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is as follows:

1. An electrical connector for establishing connection with a pair of electrical conductors comprising a pair of arms operative to surround one of said conductors with one of said arms apertured to receive the other of said conductors, a pin extending slidably through substantially the central portion of said last mentioned arm in alignment with the aperture therein that receives said last mentioned conductor and displace'able under pressure exerted by the binding relation of said arms with said first mentioned conductor for gripping said second mentioned conductor in said last mentioned arm, adjustable means interconnecting adjacent ends of said arms, a rack member pivotally connected with the opposite end of one of said arms, and a confining pin carried by the adjacent end of the other of said arms and adjustably engageable by spaced recesses in said rack member for adjustably positioning said connector with respect to said first mentioned conductor.

2. An electrical connector for establishing connection with a pair of electrical conductors comprising a pair of arms operative to surround one of said conductors with one of said arms apertured to receive the other of said conductors, an electrically conductive pin extending slidably through substantially the central portion of said last mentioned arm in alignment with the aperture therein that receives said last mentioned conductor and displaceable under pressure exerted by the binding relation of said arms with said first mentioned conductor for gripping said second mentioned conductor in said last mentioned arm, adjustable means interconnecting adjacent ends of said arms, and a latch member pivotally mounted on the opposite end of one of said arms, a pin member carried by the adjacent opposite end of the other of said arms, rack teeth disposed in spaced relation on said latch member and angularly inclined toward the pivotal end thereof, the latch member having the rack teeth adjustably engageable with the pin carried by said second mentioned arm.

3. An electrical connector comprising a pair of arms of good electrical conductivity having coacting arcuate shaped portions operative to grip the sides of an electrical conductor, said arms terminating in substantially parallel spaced end portions, an adjustable screw extending through adjacent end portions of said arms, an adjustable interconnecting toothed rack adjustably connecting the opposite spaced end portions of said arms for drawing said arms together, a conductor receiving recess in one of said arms and a longitudinally extending pin slidable through said last mentioned arm and into the recess therein and bifurcated at one end for establishing vice-like connection with another electrical conductor inserted through the recess and between the bifurcated portions of said pin, whereby the bifurcated end of said pin is forced into contacting relation with said last mentioned electrical conductor by pressure on the other end thereof communicated from the binding relation of said arms with said first mentioned electrical conductor.

4. An electrical connector for establishing connection with a pair of electrical conductors comprising a pair of arms of good electrical conductivity surrounding one of said .conductors with one of said arms apertured to receive the other of said conductors, a conductive pin slidable in said last mentioned arm through an aperture that is aligned with the aperture that receives said last mentioned conductor, said-conductive pin being retained within confined limits in said last mentioned arm in a direction substantially normal to the axis of said first mentioned conductor and di'splaceable under pressure exerted by the bindingrelation ofsaid arms with said first mentioned conductor for gripping said second mentioned conductor which passes through the aperture in said last mentioned arm, and means for drawingsaid arms together. I

'5. An electrical connector for establishing connection with a pair of electrical conductors comprising a pair of arms of good electrical conductivity operative to surround one of said conductors, one of said arms having an aperture therein extending in a direction substantially parallel with the axis of said aforementioned conductor for receiving the other of said conductors, a pin slidably extending through substantially the center of said last mentioned arm in a direction substantially normal to the aforementioned aperture in said arm and having a point on one end and a bifurcation on the other end, said bifurcation being operative to embrace the last mentioned conductor at one end of said pin and said point being operative to penetrate the first mentioned conductor at the other end of said pin, said pin communicating pressure from one of said conductors to the other for establishing electrical connection therebetween, and means for drawing said arms together.

6. An electrical connector for establishing connection with a pair of electrical conductors comprising a pair of arms of good electrical conductivity operative to surround one of said conductors with one of said arms apertured to receive the other of said conductors, a pin member slidably extending through substantially the center of said last mentioned arm and establishing abutting contact at one end with one of said conductors and bifurcated at the other end for eifecting tangential contact at spaced positions on the other of said conductors, said pin member being displaceable under pressure exerted by the binding relation of said arms with said first mentioned conductor for gripping said second mentioned conductor in said last mentioned arm, and means for drawing said arms together.

7. An electrical connector for establishing connection with a pair of electrical conductors comprising a pair of electrically conductive arms operative to surround one of said conductors, a central enlargement formed transversely of one of said arms with an aperture extending through said central enlargement in a direction substantially parallel with the axis of said first mentioned conductor for receiving the other of said conductors, a conductive pin extending through the central enlargement in said last mentioned arm in alignment with the aperture therein and confined for limiting sliding movement through said central enlargement of said last mentioned arm and displaceable under pressure exerted by the binding relation of said arms with said first mentioned conductor for gripping said second mentioned conductor at its position extending through the aperture in said last mentioned arm, adjustable means interconnecting adjacent ends of said arms, an adjustable latch engageable with the opposite adjacent ends of said arms, and means for drawing said arms together.

8. An electrical connector for establishing connection with a pair of electrical conductors comprising a pair of electrically conductive arms operative to surround one of said conductors with one of said arms apertured to receive the other of said conductors, means extending slidably through substantially the central portion of said 7 v last mentioned arm and dispiaceable under pressure exerted by the binding relation of said arms with said first mentioned conductor for gripping said second mentioned conductor in said last mentioned arm, said means comprising a pin having a frusto-conical penetrating portion on one end and a bifurcated portion on the other end and confined for limited movement in said last mentioned arm, adjustable means interconnecting adjacent ends of said arms, and a toothed rack pivotally connected with the opposite end of one of said arms and adjustabiy engageabie with the opposite adjacent end of the other of said arms.

ALFRED B. DOWNS, JR.

REFERENCES CITED The following references are of record in the file of this patent:

5 UNITED STATES PATENTS Number Name Date 56,894 Brown Aug. '7, 1866 2,071,959 Wayman Feb. 23, 1937 2,216,309 Bissell Oct. 1, 1940 2,396,119 ONeil Mar. 5, 1946 

